1. Field
Aspects of embodiments according to the present invention relate to a touch screen system, and more particularly, to a touch screen system capable of multi-touch recognition and a method of driving the same.
2. Description of Related Art
A touch screen panel is an input device capable of selecting the indication content displayed on the screen of an image display device, by using a human hand or an object in order to input the command of a user.
Therefore, the touch screen panel is provided on the front face of the image display device to convert a contact position selected by the human hand or the object into an electrical signal. Therefore, the instruction content selected at the contact position is received as an input signal. Since the touch screen panel may replace an additional input device (e.g., a keyboard or a mouse) coupled to the image display device, the applications of the touch screen panel are gradually increasing.
Methods of realizing a touch screen panel include a resistance layer method, a photo-sensing method, and a capacitive method. Recently, interest in a multi-touch screen system capable of multi-touch recognition through the touch screen panel is increasing.
In particular, in the case of the capacitive method, multi-touch recognition may be realized by a self capacitive method and a mutual capacitive method using a principle in which a change in the capacitances generated by sensing cells (nodes) positioned on a contact surface, is detected to recognize a contact position when at least one finger contacts the surface of the touch screen panel.
However, in the case of the above method, it is difficult to realize minute contact position recognition through the contact performed by the finger.
In order to solve the above problem, a stylus having a pointed end may be used. However, in the case of a passive stylus, the change in the capacitances generated by the sensing cells positioned on the contact surface is extremely slight so that it is difficult to detect a contact position. In the case of an active stylus in which an electric field is generated by the active stylus, not only the sensing cell (node) of the touch screen panel in the actual contact position, but also the other sensing cells (nodes) coupled to sensing lines are affected by the generated electric field so that it is not possible or very difficult to grasp the contact position.